I worked at a company that displayed user-uploaded photos online and in email newsletters. Some small portion of photos displayed very incorrectly only in the email newsletters as displayed by outlook. They were fine everywhere else.

After a lot of investigation, we discovered that only photos uploaded by one specific (prolific) person had this issue. And it was caused by their software putting some nonsense exif DPI data in the image that was ignored as nonsense by every renderer except outlook. The format is a minefield of features with inconsistent support.

But I suppose that's part and parcel with actually being used. And that's somewhat better than the alternative.